LONDON -- Iceland PLC Chairman Malcolm Walker quit the supermarket chain he founded 30 years ago after uproar over four million shares he controversially sold in December for 13.5 million pounds ($19.7 million or 21.3 million euros), just days before the group's share price crashed because of poor sales. The group also warned that pretax profit for the year to April, before items, is likely to be 62 million pounds, half the 120 million...